The July Days refers to an attempted Bolshevik coup that took place in Petrograd (St Petersburg), Russia, between July 4 and July 7 (Julian calendar) (July 16-July 20, Gregorian calendar) in 1917, when soldiers and industrial workers in the city, some bearing Bolshevik standards, rioted against the Provisional Government that was heading Russia at the time. After the riots began the Bolsheviks debated on the likely outcome and decided to take control as they believed the 'proletariat' were ready to defeat the Provisional Government and believed there would be a second Revolution.

The riots were crushed easily by police. Significantly, the outcome of the July Days represented a temporary decline in the growth of Bolshevik power and influence in the period before the October Revolution, because even though it was withdrawn rather quickly, the Bolshevik support for the riots was obvious.

Alexander Kerensky, the head of the Provisional Government, ordered the arrest of Vladimir Lenin and the other leading Bolsheviks, accusing them of inciting revolt with German financial backing. Lenin successfully fled the country and went into hiding in Finland, but many others were arrested, including Leon Trotsky and Lunacharskii who were apprehended on July 22.